Excessive for what?
Judging from your profile and other threads I'd say it's too much unless you are eating about double of what you said in one post ( 1400) you are young and growing the minimum for a teen female is 1600 cal. If you are walking 3 hours at a good pace you will probably burn well over 1000 cal so you will need to eat about 3K calories on your walking days.
See a doctor to discuss exercise and nutrition
I agree. Its good but you should be eating more as you know. I know you are working on it too though. Is this walking all at once or part of your vacay activities?
all at once
A little much unless you get eating more :)
What you eat can have a direct effect on your skin if you're struggling with psoriasis. See what to shop for.